Anti-inflammatory and antipyretic potential of Arbutus andrachne L. methanolic leaf extract in rats

ABSTRACT

Objective: To explore the anti-inflammatory and antipyretic effects of methanolic leaf extract from Arbutus andrachne and its mechanism of action. Methods: Paw edema was induced by intraplantar (i.pl.) injection of λ-carrageenan (1% w/v, 100 μL/paw) while pyrexia was evoked by intraperitoneal (i.p.) injection of 20% baker's yeast (20 mL/kg body wt) in male Wistar rats. The anti-inflammatory and antipyretic effects of Arbutus andrachne methanolic leaf extract were explored by injecting rats with different doses of the plant extract (150, 300, and 600 mg/kg body wt, i.p.). Selective antagonists for transient receptor potential vanilloid-1 (TRPV1), cannabinoid receptor 1 (CB1), and alpha-2 adrenergic receptor (a2-AR) were used to unravel the extracts' mechanism of action. Blood samples were collected from the heart of rats to measure the levels of interleukin-6 (IL-6) and prostaglandin E 2 (PGE 2) by enzyme-linked immunosorbent assay. Results: The extract exhibited potent anti-inflammatory activity by decreasing paw thickness and IL-6 levels. In addition, yeast-evoked pyrexia was attenuated by the extract treatment via TRPV1 and CB1 receptors and a reduction in PGE 2 levels. No significant effects were found for a2-AR. Moreover, the rats that received the plant extract demonstrated similar responses to the positive control group. Conclusions: Arbutus andrachne can be a good candidate for treating inflammation and pyrexia and should be further investigated.